raise an eyebrow [one's eyebrows] (at...)
Even if you're shopping with people you know, they might raise an eyebrow when you start haggling, but they'll sure be jealous when you get a better price than they did!
When she says she wants to talk more, raise an eyebrow and ask her if she'd like to talk in bed?
"When you misplace your keys when you're 25, you don't pay any attention to it," he said. "But when you do the identical thing at 50 or older, you raise an eyebrow."
An intriguing item on the news pages caused me to raise an eyebrow over my morning coffee.
She did not so much as raise an eyebrow.